title: Exposure system and dosimetry for in vitro studies of biocompatibility of pulse-modulated RF signals of ultrahigh field MRI.
abstract: A new setup for exposure of human cells in vitro at 37 °C to pulse-modulated 300 and 500 MHz signals of future magnetic resonance imaging (MRI) systems is designed, built up, and characterized. Two dipole antennas, specifically designed for ultrahigh field MRI, are used as radiating structures. The electromagnetic (EM) field distribution inside the incubator containing the cells is computed, and it is shown to be in a good agreement with measurements. The electric field at the cell level is quantified numerically. Local, 1-g average, and averaged over the culture medium volume SAR are provided along with the standard deviation values for each well. Temperature increments are measured inside the culture medium during the exposure using an optical fiber thermometer. Then, we identify the pulse parameters corresponding to the thermal threshold of 1 °C, usually considered as a threshold for thermally induced biological effects. For these parameters, the induction of heat shock proteins is assessed to biologically verify a potential thermal response of cells. The data demonstrate that, under the considered experimental conditions, exposure to pulse-modulated radiations emulating typical ultrahigh field MRI signals, corresponding to temperature increments below 1 °C, does not trigger any heat shock response in human brain cells.
authors.forename: Maxim
authors.initials: M
authors.lastname: Zhadobov
authors.forename: Guillaume
authors.initials: G
authors.lastname: Ferrand
authors.forename: Michel
authors.initials: M
authors.lastname: Luong
authors.forename: Yonis
authors.initials: Y
authors.lastname: Soubere
authors.forename: Catherine
authors.initials: C
authors.lastname: Le Quément
authors.forename: Pierre-Henri
authors.initials: PH
authors.lastname: Carton
authors.forename: Yves
authors.initials: Y
authors.lastname: Piret
authors.forename: Ronan
authors.initials: R
authors.lastname: Sauleau
authors.forename: Yves
authors.initials: Y
authors.lastname: Le Dréan
mesh_terms: D018929:Cell Culture Techniques; D045744:Cell Line, Tumor; D002468:Cell Physiological Phenomena / Q000528:radiation effects*; D004574:Electromagnetic Fields; D006360:Heat-Shock Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008954:Models, Biological; D011846:Radio Waves; D011874:Radiometry / Q000295:instrumentation* / Q000379:methods; D013696:Temperature
chemical_list: D006360:Heat-Shock Proteins